Abstract: Stability of output voltage of high-voltage accelerating stabilized power supply for electron beam welder(EBW) is a prerequisite to ensure the electron beam welding quality.The common power supplies have the disadvantages of circuit complexity and bulkiness.A novel control system of high-voltage accelerating stabilized power supply for EBW was designed.Its main circuit is based on pulse-width modulation(PWM) buck-boost converter topology.Compared with common EBW power supplies,this new power supply requires a much lower voltage grade transformer because of the converter's effect for rising voltage,so its volume is smaller and the circuit is simpler.The system main circuit characteristics and its working process were analyzed.The system circuit's small-signal mathematical model was created,and lag-lead correction compensation control was employed in the system to achieve static and dynamic performance requirements.The results displayed that this unit had the characteristics of fast response,high reliability,high control precision and anti-interference capability.